Field of the Invention
The invention relates to an aluminum electrolytic capacitor assembly that is fitted in a metallic housing, which, in places, has insulation composed of shrink sleeving, and, which is intended for use on a mounting plate.
Such capacitors are known, for example, from the xe2x80x9cAluminum electrolytic capacitorsxe2x80x9d data book from Siemens Matsushita Components, 1994 issue, pages 117 to 121. The mounting plate is generally composed of metal and is used to dissipate heat losses that are produced during operation of such highly rated capacitors. The mounting is provided with the aid of ring clamps or attachment bolts. For insulation, insulating disks need to be arranged between the capacitor and the mounting plate.
For optimum heat dissipation via the cup base, the insulating layer on the base should be made as thin as possible. However, such thin insulating disks are impossible because, for handling reasons, they cannot be made less than a certain thickness.
Furthermore, for insulation reasons, it is expedient not to have any uninsulated points on the capacitor housing in the vicinity of the mounting plate. Although sizing the shrink sleeving to engage slightly around the housing base is possible, it also will cause undesirable gaps where the heat transfer is poor to occur between the housing base and the mounting plate. In order to overcome this difficulty, DE-UM 296 17 888 proposes that a step be arranged on the cup base. However, this reduces the diameter of the base, so that less heat can be dissipated. Furthermore, such an arrangement creates a risk of the housing being tilted with respect to the mounting plate if the housing is attached by means of a VELCRO(copyright) fastener.
It is accordingly an object of the invention to provide an aluminum electrolytic capacitor assembly that overcomes the herein afore-mentioned disadvantages of the heretofore-known devices of this general type and that mounts on a plate while minimizing the heat retained by the capacitor.
With the foregoing and other objects in view, there is provided, in accordance with the invention, an aluminum electrolytic capacitor assembly for use on a mounting plate including an aluminum electrolytic capacitor having connections and a region surrounding the connections; a metallic housing having an insulation composed of shrink sleeving and a cup base holding the aluminum electrolytic capacitor; the shrink sleeving surrounding the housing to such an extent that only the connections, the region, the cup base, and a part of the housing adjacent to the cup base are free; and a plastic cap arranged on the cup base for insulation, the plastic cap being drawn around the cup base toward the connections.
In accordance with another feature of the invention, the plastic cap overlaps the shrink sleeving. Alternatively, an edge of the shrink sleeving can overlap the plastic cap.
In accordance with another feature of the invention, the aluminum electrolytic capacitor assembly further includes an adhesive attaching the plastic cap to the cup base.
In accordance with another feature of the invention, the plastic base defines a hole while the base includes a bolt threaded to engage the hole.
In accordance with another feature of the invention, the plastic cap is composed of polyester.
The object of the present invention is to develop the aluminum electrolytic capacitor assembly cited initially in such a way that the above-mentioned difficulties are avoided.
This object is achieved according to the invention by extending the shrink sleeving extends into the vicinity of the cup base, and, in that, a plastic cap is arranged on the cup base for insulation.
Other features that are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an aluminum electrolytic capacitor assembly, it is nevertheless not intended to be limited to the details shown, because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.